The present invention relates to a data storage medium to which files managed using a volume/file structure are recorded and reproduced, and in which the number of data recording operations to any same area is limited, and to a data recording and reproducing method and data recording and reproducing apparatus using this data storage medium. More particularly, the present invention relates to a data storage medium having a volume/file structure for retrieving the latest file management information, which is recorded continuously in the space in file addition units for managing file information and address information for unrecorded areas in the volume space and can be reproduced in series to make access faster, and relates to a data recording and reproducing method and a data recording and reproducing apparatus using this data storage medium.
While media of various types have been used in recent years for recording digital data, CD-R discs in particular have quickly become commonly used as a low-cost recordable optical disc medium. The multi-session method is now well known as a technique for writing data to these CD-R discs; a data recording operation using this multi-session method is described next below with reference to the accompanying figures.
FIG. 14 shows the data structure of a CD-R disc to which files managed using the volume/file structure defined in the ISO 9660 standard are recorded using a multi-session method. In a multi-session recording method, files and file structure and volume structure for managing files are recorded in session units. Each session has a lead-in area, an inner link area, a user data area, and a lead-out area. It is to be noted that only the first session does not have a lead-in area; an outer link area is formed between sessions.
When recording data by session unit, a file and file structure and volume structure for managing the file are first recorded to the user data area. In order to make data reproduction easier for a CD-ROM drive, which is unable to detect a location in a unrecorded area of a CD-R disc because it is unable to detect the wobble address recorded to the CD-R disc, data containing address information is also recorded to the lead-out area, and data containing start address information for the next session is recorded to a lead-in area, when the CD-R disc is removed from the CD-R drive. The user area, lead-in area, and lead-out area are each recorded in separate data recording operations. The data recorded in the data recording operation for each area is the recording data with a link block and run-in block, or a run-out block and link block, added therebefore and thereafter. An inner link area or an outer link area comprising a run-out block, link block, and run-in block is thus formed at the junction between these areas.
A multi-session data recording operation is described next below. FIG. 15 shows the directory structure used for managing files recorded to a CD-R disc. The directory structure shown in FIG. 15 has a subdirectory (Dir-A) for managing a data file (File-a), a subdirectory (Dir-B) for managing a data file (File-b), and a subdirectory (Dir-C) for managing a data file (File-c) below the root directory. When data file (File-a), data file (File-b), and data file (File-c) are recorded during a first session, second session, and third session in accordance with this directory structure, the data structure described above with reference to FIG. 14 is formed on the CD-R disc.
FIG. 16 is a flow chart describing a recording operation for creating a disc with the data structure shown in FIG. 15. The data recording operation performed each session is described next below according to the steps shown in this flow chart.
(S1601) When a CD-R disc is inserted into the disc recorder, the disc recorder accesses the lead-in area reserved at a specific location at the inside circumference of the disc, and attempts to read the TOC data from this lead-in area. If the TOC data is reproduced from the lead-in area, a step (S1602) for retrieving the following session data is performed. However, if the data could not be reproduced because the lead-in area is unrecorded, the session data recording operation is performed according to the procedure beginning in step (S1603).
(S1602) If the TOC data is reproduced from the lead-in area, the disc recorder reads the start address of the following session contained in this TOC data, returns to step (S1601), and then tries to reproduce data from the lead-in area of the following session.
(S1603) When a lead-in area to which no data is recorded is detected, the file recorded as the session data and the file structure and volume structure for managing said file are generated as follow.
First, when data is not reproduced from the first lead-in area, the data file (File-a) to be recorded as the data for the first session, subdirectory (Dir-A) for managing data file (File-a) and a directory file for managing the root directory, and volume/file structure, such as a primary volume descriptor and path table, for managing these files and the directory file, are generated according to the ISO 9660 standard.
If TOC data is reproduced from the first lead-in area, the volume/file structure and directory file are read using the user data area start address contained in the last read TOC data. For example, with a disc to which only a first session has been recorded, data is read from user data area 1402; with a disc that has been recorded through a second session, data is read from user data area 1405. The content of the volume/file structure is then updated by adding the file to be recorded and a directory file for managing said file to the read data. For example, a new volume/file structure is generated data by adding file (File-b) and the directory file (Dir-B) of the subdirectory for managing data file (File-b) to the data read from user data area 1402 on a disc to which only a first session has been recorded; and by adding data file (File-c) and the directory file (Dir-C) of the subdirectory for managing data file (File-c) to the data read from user data area 1405 on a disc to which a second session has also been recorded.
(S1604) When the volume/file structure to be recorded to a user data area is generated, a lead-in area and run-out block of predetermined recording size are skipped, and the recording data generated in step (S1603) to which a predefined link block/run-in block and link block/run-out block have been added therebefore and thereafter is continuously recorded.
(S1605) When data recording to the user data area is completed, recording data having a predefined link block/run-in block and link block/run-out block added before and after the data recorded to the lead-out area is generated. The resulting recording data is then recorded continuously from the link block following the run-out block recorded in step (S1604). When recording the first session, for example, this operation records lead-out area 1403 and the link block/run-in block and run-out block/link block located therebefore and thereafter. When recording a second session, this operation records lead-out area 1406 and the link block/run-in block and run-out block/link block located therebefore and thereafter.
(S1606) When data recording to the lead-out area is completed, the start address of the next session is calculated with consideration for the predetermined recording size of the outer link area. The calculated start address of the next session is then embedded in the TOC data recorded to the lead-in area together with the start address for the user data area recorded in step (S1604).
Recording data comprising predefined link block/run-in block and run-out block/link block units before and after the recording data for the lead-in area is then generated. The resulting recording data is then recorded continuously from a specific position at the inside circumference of the disc if the first session is being recorded. As a result of this recording operation, lead-in area 1401 and the run-out block/link block located immediately thereafter are recorded in the recording operation for a first session, for example. In a recording operation for a second session, the lead-in area 1404 and the link block/run-in block and run-out block/link block units positioned therebefore and thereafter are recorded, and the data recording operation ends.
The data recording operation described above forms a multi-session data structure such as shown in FIG. 14 on the disc. A logical sector number (LSN) is assigned to each sector in the data structure shown in FIG. 14 with the first sector in the user data area in the first session designated 0, and the logical sector number rising continuously at each successive sector. The volume space is defined as the area beginning from the sector at LSN 0.
The operation whereby a data file (File-a) is reproduced from the first session of a disc having a data structure as shown in FIG. 14 is described next below with reference to FIG. 14 and FIG. 16.
When a CD-R disc is inserted to a disc reader, the disc reader follows the procedure shown in steps (S1601) to (S1603) in the flow chart in FIG. 16 to read the latest volume/file structure 1420 from the user data area of the third session. If a CD-ROM drive is connected to a computer system, the host computer obtains the start address for the user data area of the third session to which the latest volume/file structure is recorded by executing a READ TOC command. Using this start address, it then calculates the LSN of the sector to which the latest volume/file structure is recorded, and reads this structure from the disc.
Next, when the latest volume/file structure 1420 is read, the structure is interpreted according to the ISO 9660 standard using the primary volume descriptor 1421, path table 1422, root directory 1423, and directory file (Dir-A) 1424 for managing data file (File-a) 1425. The recording position of the data file is then read from the directory record of the data file (File-a) 1425 contained in directory file (Dir-A) 1424.
The data file (File-a) 1425 recorded to the user data area of the first session is then reproduced based on said data file recording position.
With the multi-session method as described above, a lead-out area must be recorded to form a session each time a file is recorded.
Furthermore, with the data structure of a disc recorded using this multi-session method, the latest file structure recorded to the last session is read by reading in series the address information of the following session from the lead-in area of each session, starting from the address information of the next session recorded to the lead-in area of the first session.
In addition, this address information reading operation must be accomplished by running a READ TOC command or other special command instead of using the standard READ command used for reproducing files from the volume space. The present invention solves the above-noted problem, and has as an object enabling writing in file units without requiring a finalizing process such as recording a lead-out area each time a file is written, and enabling the latest file structure to be read at high speed using a standard READ command.
The above noted object is achieved by a data structure such as that of a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, wherein the data storage medium is characterized by an area for continuously recording a plurality of chaining information areas to which is recorded chaining information containing root directory file management information having location information for a next root directory file allocated for update recording, and unallocated area management information having location information for a next unrecorded area.
The above noted object is achieved by a processing sequence such as that of a data recording method for applying a formatting process to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording method characterized by a volume structure recording step for recording volume structure; an open integrity information recording step for recording open integrity information indicating a formatting process start status; an unallocated chaining information area address calculation and registration step for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where chaining information is continuously recorded; a root directory file recording step for recording a root directory file; and a chaining information recording step for recording chaining information.
The above noted object is achieved by a processing means such as that of a data recording apparatus for applying a formatting process to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording apparatus characterized by a volume structure recording means for recording volume structure; an open integrity information recording means for recording open integrity information indicating a formatting process start status; an address calculation and registration means for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where chaining information is continuously recorded; a file structure recording means for recording a root directory file; and a chaining information recording means for recording chaining information.
The above noted object is achieved by a processing sequence such as that of a data recording method for recording a file to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording method characterized by a volume structure reproducing step for reading volume structure recorded in a formatting process; a chaining information reproducing step for reading the latest chaining information while reading in series completely recorded chaining information according to previously read volume structure content; a file structure reproducing step for reading a file structure; a file recording step for accomplishing data file recording; a file structure recording step for accomplishing file structure recording; an address calculation and registration step for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where a plurality of chaining information is continuously recorded; and a chaining information recording step for recording chaining information.
The above noted object is achieved by a processing means such as that of a data recording apparatus for recording a file to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording apparatus characterized by a volume structure reproducing means for reading volume structure recorded in a formatting process; a chaining information reproducing means for reading the latest chaining information while reading in series completely recorded chaining information according to previously read volume structure content; a file structure reproducing means for reading a file structure; a file recording means for accomplishing data file recording; a file structure recording means for accomplishing file structure recording; an address calculation and registration means for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where a plurality of chaining information is continuously recorded; and a chaining information recording for recording chaining information.
The above noted object is achieved by a processing sequence such as that of a data recording method for applying a closing process, for preventing a performance drop resulting from wrong access to an unrecorded area, to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording method characterized by a volume structure reproducing step for reading volume structure recorded in a formatting process; an integrity information reproducing step for reading the latest integrity information while reading in series completely recorded close integrity information and open integrity information according to previously read volume structure content; a chaining information reproducing step for reading the latest chaining information while reading in series completely recorded chaining information according to previously read volume structure content; a file structure reproducing step for reading a file structure using the read chaining information; an unallocated chaining information area address calculation and registration step for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where chaining information is continuously recorded; a chaining information recording step for recording chaining information; an overrun extent recording step for recording an overrun extent for preventing wrong access to an unrecorded area in a file structure and file reproducing operation; and a close integrity information recording step for recording close integrity information indicative of recording completion.
The above noted object is achieved by a processing means such as that of a data recording apparatus for applying a closing process, for preventing a performance drop resulting from wrong access to an unrecorded area, to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording apparatus characterized by a volume structure reproducing means for reading volume structure recorded in a formatting process; an integrity information reproducing means for reading the latest integrity information while reading in series completely recorded close integrity information and open integrity information according to previously read volume structure content; a chaining information reproducing means for reading the latest chaining information while reading in series completely recorded chaining information according to previously read volume structure content; a file structure reproducing means for reading a file structure using the read chaining information; an unallocated chaining information area address calculation and registration means for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where chaining information is continuously recorded; a chaining information recording means for recording chaining information; an overrun extent recording means for recording an overrun extent for preventing wrong access to an unrecorded area in a file structure and file reproducing operation; and a close integrity information recording means for recording close integrity information indicative of recording completion.
The above noted object is achieved by a processing sequence such as that of a data recording method for applying a opening process for beginning recording data to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording method characterized by a volume structure reproducing step for reading volume structure recorded in a formatting process; an integrity information reproducing step for reading the latest integrity information while reading in series completely recorded close integrity information and open integrity information according to previously read volume structure content; a chaining information reproducing step for reading the latest chaining information while reading in series completely recorded chaining information according to previously read volume structure content; an open integrity information recording step for recording open integrity information; and an unallocated chaining information area address calculation and registration step for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where chaining information is continuously recorded.
The above noted object is achieved by a processing means such as that of a data recording apparatus for applying a closing process, for preventing a performance drop resulting from wrong access to an unrecorded area, to a data storage medium in which a file managed using a volume/file structure is recorded and reproduced from one end of a data recording area, and in which a number of data recording operations to a same area is limited, the data recording apparatus characterized by a volume structure reproducing means for reading volume structure recorded in a formatting process; an integrity information reproducing means for reading the latest integrity information while reading in series completely recorded close integrity information and open integrity information according to previously read volume structure content; a chaining information reproducing means for reading the latest chaining information while reading in series completely recorded chaining information according to previously read volume structure content; an open integrity information recording means for recording open integrity information; and an unallocated chaining information area address calculation and registration means for calculating and registering in chaining information an address of an unallocated chaining information area that is an unallocated area in an area where chaining information is continuously recorded.
The above noted object is achieved by a processing sequence such as that of a data reproducing method for reproducing a file from a data storage medium to which a volume/file structure is recorded by a formatting process and to which a number of data recording operations to a same area is limited, the data reproducing method characterized by a volume structure reproducing step for reading volume structure recorded in a formatting process; a chaining information reproducing step for reading the latest chaining information while reading in series a plurality of continuously recorded chaining information according to previously read volume structure content; a file structure reproducing step for reading file structure using the read chaining information; and a file reproducing step for retrieving and reading a file using the read file structure.
The above noted object is achieved by a processing means such as that of a data reproducing apparatus for reproducing a file from a data storage medium to which a volume/file structure is recorded by a formatting process and to which a number of data recording operations to a same area is limited, the data reproducing apparatus characterized by a volume structure reproducing means for reading volume structure recorded in a formatting process; a chaining information reproducing means for reading the latest chaining information while reading in series a plurality of continuously recorded chaining information according to previously read volume structure content; a file structure reproducing means for reading file structure using the read chaining information; and a file reproducing means for retrieving and reading a file using the read file structure
Chaining information storing management information for accessing a newly recorded data file and start address information for an unrecorded data area in the volume space is recorded each time a file is written to a data storage medium according to the present invention. This makes it possible to write data by file unit without accomplishing a finalizing process such as recording a lead-out area.
High speed access is also made possible by multiply recording chaining information to a plurality of contiguous areas so that the chaining information can be read in series from successively recorded areas.